In coin operated machines, such as pay phones, game machines, laundry machines, and food and beverage vending machines, financial losses resulting from the use of slugs, tokens and foreign coins, all hereinafter referred to as slugs, may be substantial. Many such vending machines have a coin slide for accepting coins and for activating the machine in which the coins are moved along a generally horizontal coin path by a slide or carrier. The carrier is typically configured to carry one or more coins in either a flat, horizontal orientation or in a vertical, on-edge orientation. Coin slides usually have means for detecting and rejecting coins or slugs of the wrong diameter and thickness.
Many such slugs contain magnetic material, and are hereinafter referred to as magnetic slugs or magnetic coins. In the field of vertical drop coin boxes in which coins are pulled downwardly by gravity through a fairly complex coin path, it has been known to use magnets to detect and reject magnetic slugs. For example, U.S. Pat. No. 3,452,849 teaches a device for preventing the use of magnetic slugs in vertical drop coin boxes and which employs magnets positioned to guide the movement of a magnetic slug along a slightly different coin rejection path as it falls to prevent it from reaching a coin acceptance station in which the vending machine is activated. However, this has proven difficult to apply to coin slides because it is often impractical to provide coin slides with a separate slug rejection path through which the magnetic slugs may be removed.
U.S. Pat. No. 4,315,567 discloses an apparatus for rejecting slugs rolling along a horizontal coin path where the magnetic content of the slug exceeds a selected threshold. Here a pair of movable magnets, when attracted by a magnetic coin, move into a position to permit passage of slightly magnetic coin, and moves to block the coin path when the desired magnetic threshold is exceeded. The moving magnets together with the related movement mechanism make it impractical to apply this to a coin slide in which several coins are carried side by side along parallel coin paths. In addition, the complexity resulting from moving parts increases the likelihood of malfunction as well as necessitating careful calibration.
Accordingly, it is seen that a need remains for a simple and reliable device for rejecting magnetic slugs in a coin slide of the type in which one or more coins are moved along a path by a carrier. It is to the provision of such, therefore, that the present invention is primarily directed.